1. Division of Foodborne, Waterborne, and Environmental Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, GA 30329, USA
2. CDC Regional Office for Central America and Panama, Guatemala City 01015, Guatemala
3. Universidad del Valle de Guatemala, Guatemala City 01015, Guatemala
4. Health Area of Santa Rosa, Ministry of Public Health and Social Welfare, Guatemala City, Guatemala
5. Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention (CDC), Atlanta, GA 30329, USA